The hurdy gurdy or hurdy-gurdy is a stringed musical instrument that produces sound by a crank-turned rosined wheel rubbing against the strings. The wheel functions much like a violin bow, and single notes played on the instrument sound similar to a violin. Melodies are played on a keyboard that presses tangents (small wedges, typically made of wood) against one or more of the strings to change their pitch. Like most other acoustic stringed instruments, it has a sound board to make the vibration of the strings audible.
Most hurdy gurdies have multiple drone strings, which give a constant pitch accompaniment to the melody, resulting in a sound similar to that of bagpipes. For this reason, the hurdy gurdy is often used interchangeably or along with bagpipes, particularly in French and contemporary Hungarian folk music.
Many folk music festivals in Europe feature music groups with hurdy gurdy players, with the most famous annual festival occurring at Saint-Chartier, in the Indre département, in central France, during the week nearest July 14 (Bastille Day).